This investigation was undertaken to validate three performance assessment tasks in high school physics.

The participating schools had at least covered the topic of refraction, both in classroom lectures and in laboratory activities.
Each student completed only one form of the task---either the integrated, the independent or the surrogate form.
A set of ten questions, compiled from past New York State Regents Examinations in Physics, was used as an additional measurement of student conceptual understanding.
The independent model is analogous to the station model that is currently used on three New York State assessments: the Grade 4 - Elementary Science Program Evaluation Test, the Intermediate Level Science (ILS) Test, and the Physical Setting: Earth Science Regents Exam.
Students took measurements related to the index of refraction of a plastic sample that was the focus of the initial portion of this task; the remaining questions on the assessment were generally related to the concept of the index of refraction but did not refer back to the initial sample.
The final task organization followed the surrogate model.In this model, students reviewed data that was collected and analyzed by other (fictitious) students.The students completing this task were asked to review the work presented on this assessment for errors; they evaluated the conclusions and statements presented on the assessment.Students were also asked to determine if the student work was acceptable or if this investigation should be repeated.Approximately 300 students from urban, suburban and rural districts across Western New York State participated in the study.The tasks were administered during the spring semester of the 2000--2001 school year.